The following relates to the optical arts. It especially relates to polarization independent liquid crystal optical media and to applications of same such as optical modulators and to wavefront correctors employing said polarization independent optical media, and will be described with particular reference thereto. However, the following will find application generally wherever a polarization-independent liquid crystal optical medium is advantageously applied, such as optical modulators, optical devices generally that employ phase modulation of light, in adaptive telescopes, in telecommunications applications, as a lasing system when doped with an appropriate dye, and so forth.
Polarization independent phase modulating optical media have heretofore been manufactured from polymer-dispersed liquid crystal (PDLC) material, in which droplets of nematic liquid crystal material are dispersed within a polymer matrix. A polymer concentration of about 30 wt-% or higher is generally used to provide spatially isolated liquid crystal droplets of typically several microns or less in size. Phase modulators made with these PDLC-based polarization independent optical materials have typically exhibited low effective refractive index changes between the “off” and “on” states, have required high switching voltages of around 15 volts/micron or higher, and have exhibited relatively low switching speeds.
It is believed that the relatively poor performance of these PDLC-based optical materials may be related in part to the high polymer concentration defining the polymer matrix. However, reducing the polymer concentration typically results in larger nematic liquid crystal droplets, and the larger liquid crystal droplets may result in polarization dependence. Such larger liquid crystal droplets also can degrade modulator performance.
The following provides improved apparatuses and methods that overcome the above-mentioned limitations and others.